Importance of vulcanization pressure for rubber marine fendersThe vulcanization pressure refers to the pressure per unit area of the rubber product during the vulcanization process. Except for thin-walled products such as tape, other rubber products require a certain amount of pressure during vulcanization. The pressure effect of vulcanization mainly has the following points:
1. Prevent the formation of bubbles during the vulcanization process of the rubber marine fender, and improve the compactness of the rubber.
During vulcanization, the rubber contains water and other volatile substances, as well as hydrogen sulfide gas that may be formed during the vulcanization reaction, which volatilize and escape at high temperatures, causing the rubber to generate bubbles. If a vulcanization pressure greater than the internal pressure of the rubber compound may be applied during vulcanization, the generation of bubbles can be prevented and the compactness of the rubber compound can be improved.
2. Make the rubber marine fender easy to flow and fill the mold cavity
In order to make rubber products with clear and full patterns, the rubber must be able to flow and fill the mold cavity. Especially in the vulcanization induction period when the compound is in the uncrosslinked state, the effect of vulcanization pressure is more obvious. Experiments show that for molded rubber products, if the vulcanization temperature is 100-140°C, the vulcanization pressure should be in the range of 2-4.9MPA.
3. Improve the adhesion between the rubber fender and the cloth layer
During vulcanization, as the vulcanization pressure increases, the depth of rubber penetration into the cloth layer increases, which can improve the adhesion between the rubber and the cloth layer and the flexural resistance of the rubber marine fender.
4. Contribute to the improvement of the physical and mechanical properties of vulcanizates
Experiments show that with 5MPA pressure vulcanization, its wear resistance is 10%-20% higher than that of general rubber marine fenders vulcanized under 2MPA. This is because increasing the vulcanization pressure can increase the compactness of the vulcanized rubber. However, too high vulcanization pressure will also be detrimental to the performance of rubber, because high pressure, like high temperature, will accelerate the pyrolysis of rubber molecules. In addition, the structure of textile materials under high pressure will also be damaged, resulting in a decrease in flex resistance.
Post time: May-26-2021